Those familiar with hydrocarbon conversion processes have long recognized that it is advantageous to perform these processes in a continuous manner. This has prompted the development of the so-called moving bed catalytic processes. In a moving bed process, the catalyst descends downward through a reaction zone in a compact, non-fluidized bed due to the action of gravity. That is, as catalyst is gradually removed from the bottom of the reactor, newly regenerated catalyst fed to the top of the reactor gradually moves downward to fill in the now available void spaces thereby providing a continuous bed of catalyst which is periodically renewed. An early example of this type of catalyst flow in a reactor is provided in FIG. 3 of U.S. Pat. No. 2,303,717 issued to M. H. Arveson. This particular patent teaches the use of a moving bed reaction zone and a moving bed regeneration zone, and the use of lockhoppers and stripping zones in catalyst treatment and transportation. Another example of a moving bed hydrocarbon conversion process is presented in U.S. Pat. No. 3,238,122 issued to W. A. Hagerbaumer. U.S. Pat. No. 3,725,249 issued to K. D. Vesely et al is pertinent for its teaching of a moving bed reforming operation with associated regeneration equipment. U.S. Pat. No. 3,978,150 issued to F. G. McWilliams, Jr. is pertinent for its showing of a continuous or moving bed dehydrogenation process which employs moving bed catalyst regeneration. U.S. Pat. No. 4,480,144 issued to F. A. Smith illustrates a carbon burnoff generation procedure for use with zeolitic catalyst.
U.S. Pat. No. 3,652,231 issued to the applicant is pertinent for its showing in FIG. 1 of the internal structure of a catalyst regeneration zone and the gas flows employed within the regeneration zone. This reference illustrates the use of an oxygen-containing gas stream in a carbon burnoff zone located in an upper portion of the regeneration zone, with this oxygen-containing gas stream being circulated through external lines which include cooling and pressurization means. This reference also illustrates a lower chlorination section, a subsequent drying section, and the reduction of the metallic components of the regenerated catalyst prior to the return of the reconditioned catalyst of the reaction zone. This reference also gives generalized teaching on the operation of this regeneration procedure and the associated catalytic reforming zone.
Other arrangements for providing the necessary gas flows to moving bed regeneration zones are illustrated in U.S. Pat. Nos. 3,981,824 issued to the applicant herein; 4,094,814 issued to E. S. Lemberger et al; and 4,094,817 issued to R. K. Olson et al. It is believed that heretofore it has been standard practice to remove the combustion gas from the regeneration zone and to then cool the combustion gas prior to such steps as division of the combustion gas into various streams or pressurization of the combustion gas.